Silica coating with well-defined micro-nano hierarchy for universal and stable surface superhydrophobicity

A universal method is proposed to produce superhydrophobic silica coating on the surfaces of either soft or hard substrates. The well-defined hierarchical structures can be formed by spraying, dipping and dropping the suspension of perfluorosilane-coated silica particles. Further adhesive-layer technique and the corresponding robustness mechanism have been investigated, and the created superhydrophobic surface shows high robustness and performance maintenance after various types of damages, including finger wiping, knife scratching and even 60 of abrasion cycles with sandpaper. Such a surface superhydrophobicity can also fit for the requirements of self-cleaning and oil separation/adsorption.